Contents

Before the events of Digimon Adventure 02, Ken feels that he is neglected by his parents in favor of his older brother Sam Ichijouji, who's been a child prodigy. At times, Ken gets along very well his brother and even shows admiration for him, but because of the lack of attention he also finds himself jealous of Sam, sometimes wishing that he was an only child.

One day while with Sam in his room, a Digivice comes out of Sam's computer. It is meant for Ken but neither of them know this, so Sam picks it up and puts it in his drawer, telling Ken not to touch the drawer until he can figure out what it is. When Sam leaves the room, Ken, in childish curiosity, touches the Digivice and is dragged through Sam's computer into the Digital World. It is there that he meets Wormmon and helps Ryo Akiyama in fighting Millenniummon. However, when Millenniummon is defeated, he forces out pieces of his data in the form of Dark Spores. Ken pushes Ryo out of the way, and one of the Spores strike him, sinking inside his neck.

Wormmon and Ryo tend to the boy for three weeks until he is well enough to return to the Real World, where he finds that it is the same day as he had left; this is likely due to Millenniummon's ability to warp time and space.

When Sam comes back into his room and finds Ken holding the Digivice, he scathingly berates him for breaking his trust and proceeds to kick Ken out of the room. As a result, Ken again finds himself angrily wishing that Sam would just disappear.

Sometime after that, Sam dies after being hit by a car. Ken is devastated following the accident, suffering from strong feelings of guilt because he feels that he'd somehow caused Sam's death by his "wish".

Then an e-mail from a mysterious figure (revealed later to be Yukio Oikawa) tells him to use the Digivice to escape the guilt and sadness. Ken does this and is transported to the Dark Ocean. There, Ken begins to believe that the Digital World is a place for him to shape and command as his own and his Digivice turns into a dark D-3. From there, Ken adopts several aspects of Sam and very rapidly develops into a boy genius, good at virtually everything that he chooses to pursue, whether it is an intellectual activity or an athletic one, such as chess or judo. He even becomes star player of the Tamachi Soccer team where he breaks the record for scoring most goals in a league season with 45. However, as the Dark Spore develops and continues to influence him, Ken becomes cynical towards society, thinking himself to be above others and viewing everyone around him as pathetic insects beneath his notice. It is then that he sets his sights on the world which could challenge him, a world that he feels it is his destiny to control: the Digital World.

Ken as Digimon EmperorKen returns to the Digital World and, through the subtle, unseen manipulations of Arukenimon, assumes the guise of the Digimon Emperor and takes over the Digimon using Dark Rings with which he enslaves a number of Digimon, similar to the Black Gears that Devimon used on the Digimon in File Island. The Dark Rings gives each Digimon glowing red eyes and make those up to and including a certain level completely obedient. Ken often uses these as sport, such as having two of them fight in a Colosseum-style arena, and keeps them locked in a sophisticated system of cages.

Ken makes his proper introduction (as himself) during a newscast about how he wins a National Computer Programming Contest with a machine that can brush people's teeth for them. The news also mentions many of Ken's previous accomplishments as well, such as chess, Donkey Madness, soccer, and balancing the world's largest checkbook. It is said that if Ken ever moved to America, he would be able to take any college due to his intellect.

As the Emperor, Ken has many conflicts with the new DigiDestined as he plans to bring a new order to the Digital World. Ken's dark Digivice prevents the Digimon from being able to naturally digivolve, but Davis Motomiya's, Cody Hida's, and Yolei Inoue's Digimon are able to use Armor Digivolution to free his Dark Ring-enslaved Digimon. During one battle, they discover that the Control Spires allow the Dark Rings to work and also begin destroying them as well.

Finally, during a soccer game in the real world, Davis injures Ken's ankle in an attempt to block him from scoring a goal. During their next confrontation in the Digital World, Davis recognizes the scar, and Ken reveals himself. As a result, he abandons the Real World to live in the Digital World and assumes the Emperor identity permanently. During that time, he creates Dark Spirals to control Ultimate Level Digimon as well as some Champion Level Digimon like Tai's Agumon (who Ken digivolves into first a berserk SkullGreymon and then into a controllable a viral MetalGreymon through the Dark Spiral). His parents, with no knowledge of where he has gone, panic and make various televised pleas to try and search for Ken.

His downfall comes about when his creation, Kimeramon, turns on him and is subsequently destroyed by Magnamon with the aid of his own partner, Wormmon. Ken refuses to believe that he lost and proclaims he would reset the Digital World, thinking it is just a computer program or a video game that could be rewritten. When the DigiDestined explain to him that it is a real place and that Digimon are living creatures, Ken, out of shock, collapses to his knees, realizing the merciless cruelty he inflicted upon innocent lives. Moments after, Wormmon dies, causing Ken to remember and relive the grief he experienced after his brother's death. Guilt ridden, Ken staggers off to return to the real world. By the time he returns home, he'd been missing for several months.

Ken sleeps for days, in a pseudo-coma, where memories of his brother, the Digivice and his first trip to the Digital World randomly surface in his mind. When he wakes, he develops amnesia and cannot recognize his parents. Ken, in a dazed state, later travels to the Digital World and wanders aimlessly before finding himself in the Primary Village. There, he is forced to remember his malicious actions by the baby Digimon whom can angrily recall the abuse he'd inflicted. After crying out apologies in hysterics, realizing how truly sorry he is, Ken is reunited with Leafmon, the baby form of Wormmon reborn. He returns home, finally realizing he has those who love him and that he has a chance to set things right. It is revealed that Ken still has his intellect even after digimon Kaiser leaving his body,however his test scores drop for 2 semesters, causing other students to wonder what happened to his intellect.

After that, Ken vows to atone for the horrible deeds he committed as the emperor. As he does, he learns that he was used by Arukenimon when she takes all data relating to the Control Spires from the boy's computer. With Stingmon, Wormmon's Champion form, he begins the daunting task of destroying the Control Spires that he erected.

At first, upon learning that Ken is back and doing good, Davis wants to ask Ken to join the team, but none of the other DigiDestined approve the idea, particularly Cody. They are convinced that he is still evil when Ken orders Stingmon to destroy Thundermon in Primary Village. The DigiDestined believe that Thundermon is a real Digimon, but he is actually created from a Control Spire. Once the DigiDestined learn that in the next battle, they become more understanding.

Ken becomes a member of the team a little after ExVeemon and Stingmon DNA Digivolve to Paildramon, but despite joining them, Ken feels uncomfortable around the others, particularly Cody, who still strongly dislikes him for what he did in the past. However, Ken still takes part in clean up jobs and other tasks with the others, as well as helps out in all the battles against Arukenimon, Mummymon and BlackWarGreymon. Slowly over time, he begins to integrate with the the group and everyone, even Cody, becomes increasingly more accepting of his presence. Ken's place on the team is unconditionally cemented when he holds a Christmas party and invites everyone over to his home. There he is able to truly smile and laugh for the first time in a long while.

After Digimon begin to appear on Christmas Day, Ken and Wormmon go to Mexico City with Matt and Gabumon to help a Mexican DigiDestined, Rosa and her partner, Gotsumon, transport some loose Digimon back to the Digital World.

Later that night, when Ken gets home, he has a dream of his first time in the Digital World and the Dark Spore. The next day, Daemon and his Daemon Corps begin to appeared in Tokyo, and wreaks havoc while seeking Ken and the Dark Spore. But Arukenimon manages to convince Ken to come with her, using the children she "kidnapped" to motivate him.

Once inside the truck, Ken is confronted by Oikawa whom he had met at his brother's funeral a few years back, who reveals the nature of Dark Spore and copies its data into the other children, who had all been taken willingly. After the events which result with Daemon's banishment to the Dark Ocean and Oikawa's escape, Ken finally introduces his stunned parents to Wormmon and the following day, now aware of what was going on, Ken’s father is happy to help the children look for Oikawa.

By December 30, Ken and the other DigiDestined (with Matt, Izzy, and Joe Kido) are standing watch at Hikari-gaoka, waiting for the Dark Spore kids to arrive. When they are all congregated there, Oikawa arrives and begins the process that uses the Spores to convert the children's energies into an energy he could use to enter the Digital World. Ken demands to know why he was chosen and what the Control Spires are for. Oikawa, in demented glee, explains what his goals were and how Ken was involved, and proceeds to open the portal, unaware that the gate had been sealed off previously. The 02 DigiDestined follow him, only to discover that they aren't in the Digital World at all but some bizarre other dimension as a result of the sealed gate. This is when the ghost of Myotismon, an enemy of the former DigiDestined, reveals that he is behind everything. He explains how he entered Oikawa's body not long after his defeat and used Oikawa to help him in his revenge. He also abandons Oikawa's body and used the power of the Spores to digivolve into the newly resurrected MaloMyotismon, his enhanced Mega form.

The villain subjects the kids to illusions of their greatest desires. For Ken, on some subconscious level, his desire is to see himself punished by every Digimon he enslaved for what he did as the Digimon Emperor, as well as a chance to see his brother alive again. Ken's final epiphany occurs when the illusory "Sam" tells Ken that he can't change the past but can ensure a bright future for himself. Following his "brother's" final words and angry at having been manipulated yet again, Ken releass his guilt, crying out that he isn't the Emperor any more, that he is through with punishing himself and that he paid enough for his crimes. With that, he breaks through the illusion and helps fight in the final battle royale against MaloMyotismon.

Ken is notable among the main 02 Digidestined for being the only "new" member in that generation to own an original Digivice that later turned into a D-3, as well as the only one to have a crest of his own. Because of this, it is somewhat implied Ken was intended to be a DigiDestined more similar to the original eight.

Three years after the events of Our War Game! and approximately several months after the final battle with MaloMyotismon, it is discovered that Diaboromon survived his battle with Omnimon and used the time in between to reproduce as millions of Kuramon. While Tai, Matt, T.K., and Kari go with Omnimon, Angemon and Angewomon to battle Diaboromon online, the others track down the Kuramon who appear in the Real World. Omnimon manages to defeat Diaboromon.

However, Diaboromon survives through his numerous Kuramon, which proceed to flood into the real world. They reconfigure into Armageddemon and easily defeat Omnimon.

Fortunately, ExVeemon and Stingmon manage to DNA Digivolve into Imperialdramon Fighter Mode but are still defeated. Omnimon then lends them his power, and they are able to change into Imperialdramon Paladin Mode and defeat Armageddamon.

In Book Two, gets to meet the tamers that had crossed into their universe: Takato, Rika, Henry, Jeri, and their partners. He later accompanies a group of Digidestined in Book Three to the tamer universe to defend against the Demon Lords. While there, he discovers that his old friend, Ryo, is living in that universe after the events with Milleniummon. In the later battle with Barbamon, Ken gains the ability to Biomerge with his partner to form GrandisKuwagamon.

Ken's relationship with Yolei continues to evolve, even with the girl's extreme personality. When Chiyo Suzume causes the girls to attack their boyfriends, Yolei tried to smash his head in with a fire extinguisher before he escaped. He also keeps close relations with Ryo since he actually has some memories of the events dealing with Milleniummon (many of the Digidestined only possess the foggiest recollections of Ryo before he left for the tamers' universe).

In Book Seven, Ken is in the middle of selecting a college, but is back home and visiting Ryo when Rayleigh Thompson's plan to round up the tamer goes into effect. Through a strange set of circumstances (or rather, Milleniummon's intervention), he, Ryo, Cyberdramon, and Wormmon escape from the forces sent to retrieve them and flee to the park to meet up with the other tamers. Rayleigh prepared a trap there to capture them, but Ryder manages to distract and upset the careful plans enough for them to escape to the Digital World.